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Discussion Starter #41
OK, I am almost ready to put the gauge cluster in place, now I have one problem. No power to the gauges. The wires go to a six part distribution thing (not sure what is is called) but it has six places to put wires that power the gauges, so it has to be activated by by turning the the ignition on. My problems is no power, so I must have misplaced the wire that supplies the circuit for all the gauges. Mine is a Red wire, but I am not sure if that standard or done by the guy that wired mt car. Any help with this would be greatly appreciated. I know there is no power (with with the ignition on or off) and it has to have a live wire attached to it, or you get what I presently have. (No power to the gauges.) What wire is the hot wire that cornets to the six prong splitter (for lack of a better name for it).

Thanks in advance for any help you can provide.

Bob
 

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If you are still using OEM GT Relay, there are 4-wire connections that feed the lighting circuits.
Originally would be 12 GA Gray / Green wire that eventually feeds to the dash dimmer switch.
After the dimmer switch, gauge lighting illumination wires are Gray.
 

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Discussion Starter #43
If you are still using OEM GT Relay, there are 4-wire connections that feed the lighting circuits.
Originally would be 12 GA Gray / Green wire that eventually feeds to the dash dimmer switch.
After the dimmer switch, gauge lighting illumination wires are Gray.
Thanks Lindsay, I am not sure of the colors of the wires since the guy that fixed it all used different colors, but I will look tomorrow and hopefully I can figure it out. I know the "hot " lead is in that area, it is just connected to to wrong terminal.

Bob
 

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No power to the gauges. The wires go to a six part distribution thing (not sure what is is called) but it has six places to put wires that power the gauges, so it has to be activated by by turning the the ignition on. My problems is no power, so I must have misplaced the wire that supplies the circuit for all the gauges. Mine is a Red wire, but I am not sure if that standard or done by the guy that wired mt car. Any help with this would be greatly appreciated. I know there is no power (with with the ignition on or off) and it has to have a live wire attached to it, or you get what I presently have. (No power to the gauges.) What wire is the hot wire that cornets to the six prong splitter (for lack of a better name for it).
Bob
If you are still using OEM GT Relay, there are 4-wire connections that feed the lighting circuits.
Originally would be 12 GA Gray / Green wire that eventually feeds to the dash dimmer switch.
After the dimmer switch, gauge lighting illumination wires are Gray.
Thanks Lindsay, I am not sure of the colors of the wires since the guy that fixed it all used different colors, but I will look tomorrow and hopefully I can figure it out. I know the "hot " lead is in that area, it is just connected to to wrong terminal.

Bob
Bob, is it the "gauge" power that isn't energized, or the "gauge lights" that aren't working now? I assume you mean the "gauge" power. The gauge lights, as Lindsay says, are powered by the gray wires, but I assume you have that working, now that the dimmer switch isn't turned down :)

If you look at the schematic that Lindsay posted, the gauge power harness is powered by the 20 AWG (thin) red w/ black stripe wires, that are connected to the terminal block shown between the speedo and tach. The power supply for that block is also a 20 AWG red w/ black stripe wire, that connects thru the black fuse box connector, and then connects to the 2nd fuse terminal (from the right).

HTH
 

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That's a bummer Bob sorry to hear that :no: Since someone else used different colored wires,
you might have to check each wire to determine which one is the hot one. But you probably
already know that. Or just trace from the hot wire Keith mentions from the OEM schematic.

The wiring on the GT sure can be a pain to work on. Good luck, I hope you get it fixed :yup:
 

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Discussion Starter #46
Bob, is it the "gauge" power that isn't energized, or the "gauge lights" that aren't working now? I assume you mean the "gauge" power. The gauge lights, as Lindsay says, are powered by the gray wires, but I assume you have that working, now that the dimmer switch isn't turned down :)

If you look at the schematic that Lindsay posted, the gauge power harness is powered by the 20 AWG (thin) red w/ black stripe wires, that are connected to the terminal block shown between the speedo and tach. The power supply for that block is also a 20 AWG red w/ black stripe wire, that connects thru the black fuse box connector, and then connects to the 2nd fuse terminal (from the right).

HTH
Keith, it's the gauge power, somehow I didn't put the right connection for power on the block. I am going to look at this morning, I think I know where I screwed up. It is not the lighting, that works fine. I will let everyone know a little later.

Bob
 

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:thinking: Probably looking for a PINK (or RED?) - Ignition switched wire.

https://www.jalopyjournal.com/forum/threads/chevy-color-code-for-dummies.343068/
This is a list of the Chevy Color code as recognized by most wiring companies. <snip> This is meant as a helpful guide to wiring your car with the basics. By using the color code and gauge size you will be able to wire your car without using labeled wires and thereby saving you money since you only have to get certain colors that work for multiple components eg; 16 GA Pink for ignition circuits. <snip>


MAIN POWER DISTRIBUTION:
10 RED - ALTERNATOR BAT FEED, IGNITION SWITCH BAT, FUSE PANEL BAT
12 PINK - IGNITION FEED FROM IGNITION SWITCH TO FUSE PANEL
12 BROWN - ACCESSORY FEED FROM IGNITION SWITCH TO FUSE PANEL
12 PURPLE - START CIRCUIT FROM IGNITION TO "S" TERMINAL ON STARTER SOLENOID

GAUGE WIRING:
18 BLUE - OIL PRESSURE
18 GREEN - WATER TEMP
18 WHITE - TACH
18 YELLOW - VEHICLE SPEED SENSOR + TO ELECTRIC SPEEDO
18 PURPLE- VEHICLE SPEED SENSOR - TO GROUND
***FUEL GAUGE HAS CHANGED A LOT AND CAN BE PURPLE, TAN OR PINK
18 PINK - GAUGE POWER (THIS GOES TO THE IGNITION TERMINAL OF ALL GAUGES AND ONE SIDE OF THE GENERATOR LAMP) ***VOLTMETER USES THIS ALSO.
 

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Discussion Starter #48
:thinking: Probably looking for a PINK (or RED?) - Ignition switched wire.
18 PINK - GAUGE POWER (THIS GOES TO THE IGNITION TERMINAL OF ALL GAUGES AND ONE SIDE OF THE GENERATOR LAMP) ***VOLTMETER USES THIS ALSO. [/I]
Well I haven't located the hot wire, so I will try the pink or red wires.

Thanks Lindsay, I will get this thing done one way or the other.

Bob
 

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Discussion Starter #49
The wife asked if it might be a fuse, sure enough it was. The problems is still the same, I turn on the ignition and it blows the fuse (new style 12 circuit blade fuse box) I have isolated the wire that blows the fuse, still don't have any working gauges. I hate this garbage, i must have moved one of the wires out of position, which one still remains a mystery. Will try again later, time to eat something and clear my mind.

Bob
 

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The wife asked if it might be a fuse, sure enough it was. The problems is still the same, I turn on the ignition and it blows the fuse (new style 12 circuit blade fuse box) I have isolated the wire that blows the fuse, still don't have any working gauges. I hate this garbage, i must have moved one of the wires out of position, which one still remains a mystery. Will try again later, time to eat something and clear my mind.

Bob
I suspect that a gauge power wire has ended up connected to a ground terminal, likely on a gauge body.

Start by disconnecting ALL the gauge power wires from the terminal block. See if the fuse still blows. If the fuse blows, you have a short on the supply wire.

If not, confirm you have 12 v at the terminal block. Then, one by one, connect the gauge power wires back to the terminal block. One will be the shorted (mis-connected) wire.

Instead of blowing a LOT of fuses while you troubleshoot this, use an ohm meter to check for a short to ground. You have one somewhere!

HTH

Ps, I have JUST finished circuit-checking my entire electrical harness after a total rebuild. I found three connections that had come disconnected during assembly, a bad fog lamp switch, a supposedly rebuilt 1975 55 amp alternator with a bad diode and bearings (now rebuilt and waiting for me to pick up) that was bleeding 2 amps to ground. THAT was fun to diagnose! During the diagnoses process, I accidentally pulled a wire off my defrost indicator lamp, which I had cleverly installed in the dash plate under the switch instead of where it belongs, under the DS vent. So today I am pulling the dash plate to repair that and the fog lamp switch. Some days I HATE these damn cars...
 

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Discussion Starter #51
I suspect that a gauge power wire has ended up connected to a ground terminal, likely on a gauge body.

Start by disconnecting ALL the gauge power wires from the terminal block. See if the fuse still blows. If the fuse blows, you have a short on the supply wire.

If not, confirm you have 12 v at the terminal block. Then, one by one, connect the gauge power wires back to the terminal block. One will be the shorted (mis-connected) wire.

Instead of blowing a LOT of fuses while you troubleshoot this, use an ohm meter to check for a short to ground. You have one somewhere!

HTH

Ps, I have JUST finished circuit-checking my entire electrical harness after a total rebuild. I found three connections that had come disconnected during assembly, a bad fog lamp switch, a supposedly rebuilt 1975 55 amp alternator with a bad diode and bearings (now rebuilt and waiting for me to pick up) that was bleeding 2 amps to ground. THAT was fun to diagnose! During the diagnoses process, I accidentally pulled a wire off my defrost indicator lamp, which I had cleverly installed in the dash plate under the switch instead of where it belongs, under the DS vent. So today I am pulling the dash plate to repair that and the fog lamp switch. Some days I HATE these damn cars...
Keith, I will give it all a try tomorrow. sounds logical, but it also sound like a lot of work. Well I guess I don't have any choice. Thanks for the solution, I hope this works. I know what you mean about hating these damn cars.

Bob
 

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Discussion Starter #52
Well today didn't work out to well for me. I have to get everything ready for my trip to California, I want to see my sister and two daughters and three granddaughters. I have a few friends that I want to see too. So the plan is Monday to dive into the gauge problems. With Keith's and Lindsay's pointers I should be able to do it pretty quickly. (I seem to remember saying that a while back.) So the next report on the gauges won't be until Monday night, just thought I would let everyone know so you don't think I just gave up.

Bob
 

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Discussion Starter #54
Well, I finally got it. I have gauge power to all the gauges. Thee trouble spot was the oil pressure gauge. Apparently there is insulation around the jacket for the oil pressure light. for some reason it was grounding out on the slave of the gauge. I am not sure why, but everything works now.

The next step is putting the radio back in, then putting the gauge panel back into the dash.

Thanks Keith, I did what you wrote, take all the gauge power wires off the terminals and keep adding until it shorted out. Didn't take long as it was the second gauge I tested. So all is well, hope the weather lasts so I can take her for a ride. Thanks again Keith, I was at the end of my rope.

Bob
 

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WOO HOO Mr. Bob
Glad to hear you found it.:yup:
Doesn't it just drive you batty when silly stuff like this happens
I'm so thankful for all the support here on this site
Talk about a support group
Great minds at work here and somehow we all keep each other from pulling our hair out(well not in my case not much left upstairs will have to start on chest hairs) :lmao::lmao:
 

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Discussion Starter #56
Terry, you're right, many times I have needed help for just little things, could have never figured out half of them without the help from several folks on the forum. If you can't get the answer here, chances are you will never get an answer. Thanks to Lindsay and Keith for their help to get this thing fixed.

Bob
 

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Pictures

OK I am going to post the pictures of my gauges with the blue LED lights in place. The pictures are time lapse an leave a little bit to be desired, but I think you will get the picture (pun). The shop was dark because all the lights made it impossible to show the blue light. So I shut off the lights. After taking a few pictures it became evident that I need the tripod to put the camera on. While these pictures are better, the still leave a lot to be desired.


Bob
I'm surprised at how bright the blue light is on the black gauge clusters. I'm going to try white led on white face gauges. Wish someone else had a picture of that, but if not I'll eventually try to post pictures. Hope someone else posts first on these. The blue really looks good and easy to see the gauge numbers. Great job!
 
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